The invention relates to a method and apparatus for measuring the air quantity supplied to an internal combustion engine. A measurement apparatus is already known whose basic structure corresponds to a bridge circuit and a hot wire forms one of the bridge resistors. A resistor disposed in a corresponding position in the other bridge arm comprises two partial resistors, one of which is also disposed in the air intake manifold, so that this one partial resistor, located in series therewith for this purpose is disposed outside the air intake manifold. The voltage between the bridge diagonal is supplied to an amplifier and its output signal represents both a signal pertaining to the air quantity flowing in the air intake manifold and the control signal for the bridge itself. It is the object of the amplifier in the known arrangement to maintain the temperature of the hot wire or or the hot film at a constant value. However, because of this control at a constant temperature, errors in measurement result because the properties of the medium to be measured, that is, the air, are dependent on the temperature.